Quick question about source requirements?

In all of the years I've been here, I have never seen the requirement that a post concerning some unfolding event required collaboration from a MSM
source.

I noticed this posting in a thread today:

admin edit: Since this is yet another tragedy in the U.S. that is still unfolding, I've moved this thread to BAN (from Off Topic News) even though it
doesn't have the correct "sources". There were no sources available when the ATS Member "murch" posted it. The Main Stream Media hadn't reported on it
yet.

The purpose of this thread is not to dispute the requirement, if it is one. I'm just seeking clarification.

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